With the development of network technology, the network is providing people with great convenience. But due to the openness of the Internet itself, there are many hidden dangers in the network, like viruses, hacker attacks and computer threats have become commonplace, and make information disclosure. “What prevents nefarious actors from stealing information and money every time someone engages in a personal transaction online? The answer is encryption. Cryptography is the process of scrambling messages so that only desired parties can unscramble and discern their meanings by using secret keys. (Harmon, P. 2022)” Therefore, the confidentiality of information is an important aspect of information security. The purpose of confidentiality is to prevent unauthorized users from cracking confidential information. Encryption is an important means to achieve information confidentiality.